Improvement in the manufacture of dental plates from pyroxyline



UNITEDfSTAa-ns PATENT DEFICif-1- Asp 'UnrAL K.' Merger Bestron', inA'ssAeHUsErTs; 1

" -mPRovEMENTiNlTnt-MANUFACTURE or DENTAL PLATES-#RomPYRO'XYUNL Speeiation forming part of Letters Patent o. il3,73v6, dated -April 19, 18? 1.

To all persons to whom these presents may come.

Be it known that I, J osEPHUs BitooiiWAY, of the eity and county 'of Albany and State of New York, have invented zt new and useful Improvement in Dentistry', or in the Preparation of Artificial Teeth, and in the Manufnetureo Mouth-Plates or Supports therefor of P'yroxyline;.and I do, hereby deelare the sa-nie to he `fully deseribed inthe following specification nud represented in the aeeonipa- 'nying drawing of which- Figure l is n rear View, Fig. 2 a 'front elevation, and Fig-3, it transverse section, ofn toothbloek prepared for use in accordance with my invention. Fin'. 4 is a top View, and Fig. 5 n bnck view, of an upper-jaw mouthplnte, as made and prepnredin noeordztnee with my invention, for the reception of artiiieial teeth. 4lfig. 6 is a top view, Fig. Z a. bottom view, and Fig. S is a transverse seet-ion, ot' n lower-jaw bar or mouth-plate as sov made. Fig. 9 is a.. transverse section of the teeth und mouthplate for an upper jaw, as combined, as hereinafter set forth.

With my invention' I am enabled to etleet-v ngreat ehnng'e in the art of dentistry, whereby, with eolnlmratively 'little labor and expense, I can make, in a. very short period of time, u whole set or a part of rt set ot' artiticial teeth, oi' perfect tit and ot' great durability, ns well as not liable to the inconvenienees and objections et" those made with metnllie or vuleanite bases, thel substance used :uid it hns .long been a desideratuni to iindv some goed and proper substitute for suoli baseplaies. I have sueeeeded in discovering a mode by which soluble eotton may be adopted :is sueh substitutel So long ugo :is 11.559 n patent, I believe, wus secured in ilnigland for its unifier, d elntnl pluies.

The shrinkage ot' vthis'material in drying is very great, it genen a-lly'oeeupying but one-thirtieth of the space vin 'aisolid s tete'to wliiehit does es a liquider infthe' st-ntbfeollodion; .This` property ot' the prepared'eottou prev'fnited'it frombeing suevcessfullyused. IliV this "eountryatteni pts to so utilize it have beenj-inade by mixing it with mineral or other mtters, but the' 1nix-v ture 'was rendered too brittle, and was obje'ctionable in other respects. The hard collodion .has ,bejeii obtained andjsulisequently broken np, redisso lved, and afterward pressed into a; moidcontninng the tooth or teeth. As

the material hardened it would'shrink so 1n ueh V:is to require' great force to keepit in eenneetion with the teeth, they often being'broken `by it.` Besides, though dry orY hard on the exterior, vthe interior of the pluto oi'ten remained for monthsin ztsoft state, beine` sub--` jeeted to, constant shrinkage, 'all of which was fatal to it'for the intended purpose.

As'instalnees et' attempt-s to use pyroxyline @n den-tol and other purposes, reference mny be had l to the'ritish putent No. 53h', of'lSlib, to Newton; the American or United- States patents Nos. 88,288, $9,253, and 89,254 oi' Streeter; and 77,30i, 90,765, 90,765, and-96,A 132 of MeGlellam'i.v In eatrrying` ont myinvention I do not' press the mnteriaiin e mold upon or zig-einst the tooth orteeth placed therein in order to x it or them to it end giie shape to the nuiterinl, but I condense the material in n. mold and in durate the molded mass so asto reduce it to a shupe closely approximating to such us ina-y have grooves (l. I) disposed injlrffbraeriorl in manner as shown,'sueh being to serve :tS ..sup ports to the teeth and their bnekin'.

To fully dissolve the cotton" so `that it would liow into n iium or mold would not only render it brittle when in u dried stnte,'but .more or less .iilled with bubbles. To eut or dissolvelihe cotton with i-iiiierlone, or with *of the necessary form and size.

-loo little alcolici, renders it too sticky or tacky lor removal from a mold. Hence, in lorder that the ber mayretain its full strength, 'itV should lie-cut with alcohol and ether, taking eure `to employ as nearly as possible the largest axuountof alcohol and the least ofether that can well be used to eiiect thedesirable plastic condition oli' the solution.l After the plastic material. may have been produced iii/is to ber@v put into' arcylinder or vessel provided with one or more sie\'es,`and having a piston ar ranged so that, by pressure on it to force it into the cylinder, the-plastic material may be expelled through the said sieveor sieves, and to be strained thereby. Next, the piston should be subjected .to heavy pressure--sa-y,Y about ten tons,(a screw generally being em` ployeih) so osito drive-the plastic' material:

be about eight times the bulk which it -is to have when finally reduced to an indurated state. It is next to be removed from the mold, when it will be found to have the eonsistence of an ordinary b-ucliwheatcake. The next part ofthe process is the seasoning for boarding,7 ofthe material so molded. 4To Vaccomplish this the cakes orY masses may-be ex#y posed, for about twelve hours, 0n a bench or board, to the atmosphere, occasionally turning them over. I prefer to do this before sub- `iecting them to the boarding of them or .next

part of the process, although itis not essen-4 tial to my invention so to do. The object of y thus exposing the masses to the' atmosphere is to dry their outer surfaces, so as to prevent adhesion of them to the boards used inthe hoarding of them; also to allow Athem to gen# orallycontr-uciJ a little. l

r)Ehe masses or molded portions of the in'a. terial are next to be laid between flat boards, a stuck or pile ofthe boards and masses alter-z nately arranged together being made, weights being placed ou the upper or cap board, so as to press the boards and massestogether. The

object of thus boarding the masses is dto keep them-iu their fiat state, or prevent them from warping, while they may be contracting. They areto be suffered to remain between thcboards about two days, or until they may have become suiliciently hardened to be capable of Abeing pressed in dies without heilig abraded or cracked thereby, lThe next part of the process consists in pressing euch ofthe plates of the material in or between dies, so as to condense it, and give .concave side of the next one.

to it a formv approximating to that itfis to I#finally have? After this has been done,"the

plates are to he stacked together, one placed on `the other, with itsy convex side within the A. pile of the plates having thus been mad'o is to be placed between two male and female retaining-dies corresponding in vshape with H the plates, and the whole are to be' 'firmlypressed together in a screw-press, or by other suitable means, and are tube suiiered to stand exposed for about four days t0 the atmosphere, at ordinary temperature, the object being to allow the escape of the solvent or solvents and the gradual contraction of the mass, and the retaiu'ingof each plate in the general form required. Were it not for this treatment of theiplates they would curl in various ways.

out of shape. l f' The plates 4thus produced may be next exf posed to the latmosphere so as to thoroughly dry them, it being preferable to press each plate in dies occasionally while it may be dryf ing, in order to further condense it and preserveit in shape as it may contract.`

It will be observed thatwhat Igterm vthe baseplate iste have,rst, the necessary vapi-f proximate shape to-t the superior or inferior alveolar ridge of either the upperor lower.

jaw, the fitting it to the ridge being asnbseg quent matter,` and eected as follows: This-ijs,

to be done by .cuttingor reducing it by toolsto a closer t, and 4nally dusting upon the sii' face aj quantity of thennaterial in a commi-1 .nuted 'or powdered state, and pouringupon the quantity so dusted a suiicient quantity of ether or other suitable solvent, solas to 1educe it to a.' Plastic state. In this condition the plate is" to ,be pressedl upon` the plaster cast or eounterpart'of the jaw, or the portion thereof to be iitted, and there rmllheld 'by means 'of,elasticclasps or a press `until'suiciently dry or set.l i

Next, the tooth or blocks of teeth, prepared with a backing or backings, as hereinbefore explained, is or are to be affixed to the base4 plate B, they rst being articulatedina manner well known to dentista.A

Having' thus been properlyl ryrran ged on the base,'ea`ehV tooth orlocklis toibo fastened in"l place-thereon byp'utting'or filling 'into the joints and about the-backing a small amount of the powdered material, and next applying thereto ether or other proper Vsolveuin'so as to reduce they mass to a cementing state, where# by, when dry, itwiil e'cct the adhesion of thel teeth to the'baselplatelv 'i a.

That part of the ba'seplate which .is fit to the alveolar arch may be' in' a piece sepa fate from the portion to fit to the alveolar' ridge, and be connected thereto by means of the powdered material vreducedfbyV zii-solvent, as described, the whole being' ast'ofornr the part either with or without-` one orlmore air-chambers or suction-spaces, such are usually formed in the upper surface of;l thearch.

In making a plate in this Way the old method fot' using dies to t it t0 the month is dispensed with, thereby effecting a saving;` ot' a large amount of labor, expense, and time, and being advantageous in other respects,

Dental plates of pyroxyline, as made previous to my invention, and by processes Well known er described in various patents secured A both in thisconntry andin Great Britain, have generally been failures, owing` to the diliienlty experienced in producing goed plates, being,` lne to the attempts made to mold the plate from the plastic mass before suitable shrinkage of it had taken place.

Such patents are Britislrpatents No. 2,249 of li S60, 536 oflSGS, 2,359 of 1855, and the United :states patents Nos. 77 ,304, 90,765, 90,766, and

' 96,182 of John A. McClelland, also, the United roxyline, or its conversion into dental plates or Yarions other articles.

The advantage of my process of making a plate is due, in a great measure, to the intermediate step of b0arding,whicl1 1s not described in either of such patents, and which` allows the mass to loose its bulk, so that the final forming is eected in dies but a little larger than the finished plate.

The plate, when first subjected to such dies,

has shrunk to such an extent as to retain but lit-tle'of'the solvent-only enough to prevent fracturev ofit, and enable it to conform to the die or dies, so that when the plate is finished the disparity between it and the die or dies is but trilling.

l make no claim to any:4 of the s'nbjects,

things, or processes described in either of the British or United States patents hereinbefore enumerated.

I claim as my invention- A dental vplate of pyroxyline, made by rst forming the sheet by molding it, as described, and next boarding, and finally,pressing` and shrinking it, all substantially as hereinbct'ore specified.

JOSEPHUS BROGKWAY,

Vfitnesses:

1i. H. EDDY, J. lt. SNOW. 

